So I think I've nailed this down to it being time to replace my battery... My car has been throwing codes and telling me it has engine malfunction and reducing engine power.

The codes are as follows:
P156F - (not 100% sure on this one but found the description below by googling)
BATTERY CELL TEMPERATURE SIGNAL CIRCUIT PROBLEM

P1628 - Throttle Valve Actuator Bank 1 Sprint Test Malfunction

These pop up (or just the first one) then go away after some time. As far as I know, the battery has not been replaced and its about 4 years old now. Could both of these be caused by a dying battery? I know sensors and such will start to go funky when our batteries get low but don't want to replace it yet if I don't have to...

Thoughts?

(fairly certain this is the correct place to put this thread, please move it if it is not)

I would clear the codes and see if the code for the TVA comes back. It could be two separate issues. I have a scanner at the house if you want to stop by.

Eric

Hey Eric! How you been man??

So this is probably the third time I've seen these codes, they always seem to come together tho so that is why I'm thinking it might be the battery. I keep my scanner in my car so I've cleared it every time its popped up and it stays gone for a while then comes back weeks or months later it seems...

You ever replaced the TVA bits? If it keeps popping up I might have to stock up on some beer and stop by some time lol. I've got spark plugs sitting in my garage waiting to go in also. You got any maintenance to do on yours? We could have a maintenance party...

I've been ok, busy as sh*t. There is a DIY for the TVA and we can follow it. We can do it at my house. I'm getting the tool to pull the coils of the heads to change the plugs also. Let me know when you want to do that. I already had my plugs changed by the dealership last Friday. The current on the old battery might be so low that when you start your car, the TVA will act up, because not enough power to get them going???? My 0.02 cents. I would replace the battery first is my guess and then go from there.

Flip, I started seeing weird codes and battery issues a few weeks ago too. I got a battery tender from Amazon for $40 and have run it 1 night a week for the past two weeks. It seems to have cleared up my issues for now.

Flip, I started seeing weird codes and battery issues a few weeks ago too. I got a battery tender from Amazon for $40 and have run it 1 night a week for the past two weeks. It seems to have cleared up my issues for now.

I'm in Marietta too if you want to borrow/try it.

Hey David, wassup. If he is getting a cell malfunction, a charger will probably not help. But he can also try that. It is cheaper than getting a new battery.

I've been ok, busy as sh*t. There is a DIY for the TVA and we can follow it. We can do it at my house. I'm getting the tool to pull the coils of the heads to change the plugs also. Let me know when you want to do that. I already had my plugs changed by the dealership last Friday. The current on the old battery might be so low that when you start your car, the TVA will act up, because not enough power to get them going???? My 0.02 cents. I would replace the battery first is my guess and then go from there.

Awesome! Maybe we can set up a day in the next few weeks.

Yeah, that was my thought as well... It sounds like a reasonable explanation.

I'll look for a good battery and pick that up shortly. Also I think I may pick up a cable so I can set the computer for the new battery. This is what I was thinking about getting. Any idea if this one will be alright? Not looking for anything crazy, this one is cheap and looks like it should get the job done.

I'd thought about it but I do drive it enough so I shouldn't need to keep it on a tender. The battery is also right at about 4 years old so it would make sense that it needs to be replaced anyway.

Quote:

Originally Posted by dmk08

Sup Eric

Flip, I started seeing weird codes and battery issues a few weeks ago too. I got a battery tender from Amazon for $40 and have run it 1 night a week for the past two weeks. It seems to have cleared up my issues for now.

I'm in Marietta too if you want to borrow/try it.

Yeah, i'm sure it would put off the problems but if the battery is going bad it will be inevitable...

Quote:

Originally Posted by elm3

Hey David, wassup. If he is getting a cell malfunction, a charger will probably not help. But he can also try that. It is cheaper than getting a new battery.

Yeah, that was my thought as well... It sounds like a reasonable explanation.

I'll look for a good battery and pick that up shortly. Also I think I may pick up a cable so I can set the computer for the new battery. This is what I was thinking about getting. Any idea if this one will be alright? Not looking for anything crazy, this one is cheap and looks like it should get the job done.

You are right. When do you want to come over and work on your car? Mine is getting aligned tomorrow at Butler Tires. I put my wheels back on.

I'll be able to let ya know when as soon as I pick up a battery and get that cable. Would Sunday, December 9th work? I don't have anything going on then and think I could get everything together before then... We can make sure that works for everyone else wanting to join us as well!

And sweet! I want to see the wheels on yours... I still want to lower mine and do spacers eventually...

Any thoughts on if this will be OK? Would it be worth getting something closer to stock if this isn't close enough?

It is not an AGM battery as far as I can tell. It seems from the looking that I have done that there are two sizes that are factory fits, the Group 48 lead acid or H6 AGM and the Group 49 lead acid or H8 AGM. The difference is 41 lbs weight versus 58 lbs weight plus some cranking and reserve capacity. I am battery shopping also for my 08M3, and will go with AGM technology.

That H8 does look a bit closer numbers wise. Currently our cars (with stock battery) should be set at 90ah. The one I got will be 73.5 (so round to 70 when programming). The H8 comes out to 97 so it would require a change in the programming regardless... Not sure if its worth taking this one back over that or not.